PFS was defined as the time from randomization to first documented disease progression (PD) using Response Evaluation Criteria in Solid Tumors (RECIST) or death from any cause (within 18 weeks of last tumor assessment), whichever occurred first. For target lesions, PD was defined as at least a 20% increase in the sum of the longest diameter of target lesions, taking as reference the smallest sum of the longest diameter recorded since treatment started or the appearance of 1 or more new lesions. For non-target lesions, PD was defined as the appearance of 1 or more new lesions and/or unequivocal progression of existing non-target lesions. Target lesions were selected on the basis of their size (those with the longest diameter) and their suitability for accurate repeated measurements by imaging techniques or clinically. All measurable lesions up to a maximum of 5 lesions per organ and 10 lesions in total, representative of all involved organs, were identified as target lesions.

PFS was defined as the time from randomization to first documented disease progression (PD) using Response Evaluation Criteria in Solid Tumors (RECIST) or death from any cause (within 18 weeks of last tumor assessment), whichever occurred first. For target lesions, PD was defined as at least a 20% increase in the sum of the longest diameter of target lesions, taking as reference the smallest sum of the longest diameter recorded since treatment started or the appearance of 1 or more new lesions. For non-target lesions, PD was defined as the appearance of 1 or more new lesions and/or unequivocal progression of existing non-target lesions. Target lesions were selected on the basis of their size (those with the longest diameter) and their suitability for accurate repeated measurements by imaging techniques or clinically. All measurable lesions up to a maximum of 5 lesions per organ and 10 lesions in total, representative of all involved organs, were identified as target lesions.

A patient had an objective response if they had a complete response or a partial response determined on two consecutive occasions ≥ 4 weeks apart as determined by the investigator using RECIST. For target lesions, a complete response was defined as the disappearance of all target lesions; a partial response was defined as at least a 30% decrease in the sum of the longest diameter of target lesions, taking as reference the baseline sum longest diameter. For non-target lesions, a complete response was defined as the disappearance of all non-target lesions; a partial response was defined as the persistence of 1 or more non-target lesions.

Duration of objective response was defined as the time from the initial response to documented disease progression or death from any cause, whichever occurred first.

Time to Symptom Progression [ Time Frame: Baseline to data cut-off (up to 3 years, 3 months) ] [ Designated as safety issue: No ]

Time to symptom progression was defined as the time from randomization to the first symptom progression as measured by the Functional Assessment of Cancer Therapy-for patients with Breast Cancer (FACT-B) questionnaire with the Trial Outcomes Index-Physical/Functional/Breast (TOI-PFB) subscale. The FACT-B TOI-PFB subscale contains 24 items from 3 subsections of the FACT-B questionnaire: Physical well-being, functional well-being, and additional concerns for breast cancer patients (breast cancer subscale [BCS]). All items in the questionnaire were rated by the patient on a 5-point scale ranging from 0 ("not at all") to 4 ("very much"). The total score ranged from 0 to 96. A higher score indicates better perceived quality of life. A positive change score from baseline indicates improvement. Symptom progression was defined as a decrease from baseline of 5 points or more.

This study is a Phase III, randomized, double-blind, placebo-controlled, multicenter international clinical trial. Patients who have human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC) and have not received chemotherapy or biological therapy (including approved or investigational tyrosine kinase/HER inhibitors or vaccines) for their metastatic disease are eligible for study. Patients could have received one prior hormonal treatment for MBC. Patients may have received systemic breast cancer treatment in the neo-adjuvant or adjuvant setting, provided that the patient has experienced a disease-free interval (DFI) of ≥ 12 months from completion of adjuvant systemic treatment (excluding hormonal therapy) to metastatic diagnosis. Patients may have received trastuzumab and/or a taxane during the neo-adjuvant or adjuvant treatment.

* Includes publications given by the data provider as well as publications
identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.

Recruitment Information

Recruitment Status ICMJE

Active, not recruiting

Enrollment ICMJE

808

Estimated Completion Date

July 2017

Primary Completion Date

May 2011 (final data collection date for primary outcome measure)

Eligibility Criteria ICMJE

Inclusion Criteria:

Histologically or cytologically confirmed adenocarcinoma of the breast with locally recurrent or metastatic disease, and candidate for chemotherapy. Patients with measurable and non-measurable disease are eligible (locally recurrent disease must not be amenable to resection with curative intent; patients with de novo Stage IV disease are eligible).

For women of childbearing potential, agreement to use an effective form of contraception and to continue its use for the duration of study treatment and for 6 months after the last dose of study treatment.

Signed, written informed consent obtained prior to any study procedure.

Exclusion Criteria:

History of anti-cancer therapy for MBC (with the exception of one prior hormonal regimen for MBC).

History of approved or investigative tyrosine kinase/HER inhibitors for breast cancer in any treatment setting, except trastuzumab used in the neoadjuvant or adjuvant setting.

History of systemic breast cancer treatment in the neo-adjuvant or adjuvant setting with a disease-free interval from completion of the systemic treatment (excluding hormonal therapy) to metastatic diagnosis of < 12 months.